U.S. patent number 9,496,730 [Application Number 13/193,278] was granted by the patent office on 2016-11-15 for systems and methods for battery management.
This patent grant is currently assigned to Proterra Inc.. The grantee listed for this patent is Nicky G. Gallegos, Michael Walker. Invention is credited to Nicky G. Gallegos, Michael Walker.
United States Patent |
9,496,730 |
Gallegos , et al. |
November 15, 2016 |
Systems and methods for battery management
Abstract
A battery management system includes several subsystem blocks,
an Energy Storage Master unit, and several battery pack systems.
The Energy Storage Master may interface with the Vehicle Master
Controller by way of CAN or other communication method to an
External Charger. Each battery module within a battery pack may
include a Local Module Unit which may communicate with a Pack
Master. The Pack Master may communicate with and may be controlled
by the Energy Storage Master. Thus, there is a processor to monitor
groups of battery cells, a second processor to collect further
information about the cell groups, and a third module that takes
high-level information from each cell group processor to process
and pass on to other vehicle controllers or charger controllers. An
integrated BMS may enable cell monitoring, temperature monitoring,
cell balancing, string current monitoring, and charger control
integration.
Inventors: |
Gallegos; Nicky G.
(Westminster, CO), Walker; Michael (Thornton, CO) |
Applicant: |
Name |
City |
State |
Country |
Type |
Gallegos; Nicky G.
Walker; Michael |
Westminster
Thornton |
CO
CO |
US
US |
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|
Assignee: |
Proterra Inc. (Greenville,
SC)
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Family
ID: |
45773432 |
Appl.
No.: |
13/193,278 |
Filed: |
July 28, 2011 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20120105001 A1 |
May 3, 2012 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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61379671 |
Sep 2, 2010 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60L
50/40 (20190201); B60L 58/22 (20190201); B60L
3/04 (20130101); B60L 53/62 (20190201); B60L
58/13 (20190201); B60L 3/0092 (20130101); B60L
53/66 (20190201); B60L 3/0046 (20130101); B60L
58/16 (20190201); H02J 7/0016 (20130101); H01M
10/0525 (20130101); H01M 10/441 (20130101); H02J
7/0027 (20130101); B60L 58/24 (20190201); B60L
53/14 (20190201); B60L 58/14 (20190201); B60L
3/0069 (20130101); B60L 58/26 (20190201); Y02E
60/10 (20130101); Y02T 90/128 (20130101); B60L
2240/547 (20130101); Y02T 90/16 (20130101); Y02T
90/163 (20130101); Y02T 10/7055 (20130101); Y02T
10/7011 (20130101); Y02T 90/121 (20130101); B60L
2210/10 (20130101); Y02T 10/72 (20130101); Y02T
90/127 (20130101); Y02T 10/7216 (20130101); Y02E
60/122 (20130101); Y02T 10/70 (20130101); B60L
2240/36 (20130101); B60L 2250/10 (20130101); B60L
2240/545 (20130101); B60L 2240/549 (20130101); Y02T
10/7061 (20130101); Y02T 90/12 (20130101); B60L
2250/16 (20130101); Y02T 10/7072 (20130101); Y02T
90/14 (20130101); G01R 31/396 (20190101); Y02T
10/7022 (20130101) |
Current International
Class: |
H02J
7/14 (20060101); H02J 7/00 (20060101); H01M
10/0525 (20100101); H01M 10/44 (20060101); B60L
3/00 (20060101); B60L 3/04 (20060101); B60L
11/00 (20060101); B60L 11/18 (20060101); G01R
31/36 (20060101) |
Field of
Search: |
;320/104,116 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
John Ayers, Digital Integrated Circuits, 2004. cited by examiner
.
U.S. Appl. No. 13/820,709, filed Mar. 4, 2013, Gallegos et al.
cited by applicant .
International search report and written opinion dated Mar. 21, 2012
for PCT/US2011/045791. cited by applicant.
|
Primary Examiner: Rodas; Richard Isla
Assistant Examiner: Dibenedetto; Michael
Attorney, Agent or Firm: Bookoff Mcandrews, PLLC
Parent Case Text
This application claims the benefit of U.S. Provisional Application
No. 61/379,671, filed Sep. 2, 2010, which application is
incorporated herein by reference.
Claims
What is claimed is:
1. A battery management system for a battery assembly of an
electric vehicle, the battery assembly including a plurality of
battery strings connected in parallel, wherein (a) each battery
string includes a plurality of battery packs, (b) each battery pack
includes a plurality of battery modules packaged together in an
enclosure, and (c) each battery module includes multiple battery
cells packaged together in a module housing, comprising: a module
control unit associated with each battery module, wherein the
module control unit is a printed circuit board attached directly to
each battery module, and positioned within the module housing of
the battery module, wherein the module control unit associated with
each battery module is separate from the module control unit
associated with another battery module, and wherein each module
control unit is configured to detect at least a voltage, a current,
a humidity, and a temperature of a plurality of battery cells of
the corresponding battery module; a Serial Peripheral Interface
(SPI) isolation board attached to each module control unit; and a
pack control unit associated with each battery pack, wherein each
pack control unit is configured to perform cell balancing of the
battery cells of the corresponding battery pack based on the
voltages and temperatures detected by the module control units of
the battery pack, wherein the module control units and the pack
control unit of the battery pack are connected together using a
Serial Peripheral Interface (SPI) bus, and wherein the SPI
isolation board attached to each module control unit isolates SPI
signals from the module control unit to the pack control unit.
2. The system of claim 1, wherein the electric vehicle is an
electric bus, and wherein at least one battery pack of the
plurality of battery packs is positioned under a floor of the
bus.
3. The system of claim 2, wherein the pack control unit is operably
coupled to an external charger of the electric vehicle.
4. The system of claim 1, wherein ten battery cells form a battery
module, and eight battery modules form a battery pack.
5. The system of claim 1, further including an energy storage
master control unit coupled to each pack control unit of the
battery assembly, the energy storage master control unit being
configured to monitor a state of health of the battery cells of the
battery assembly and disconnect a battery string of the plurality
of battery strings from service based on the state of health of a
battery cell in the battery string to allow the vehicle to continue
operating using the remaining battery strings.
6. The system of claim 1, wherein the pack control unit is
configured to balance the multiple battery cells of the battery
pack by buffering energy from a plurality of battery cells of the
multiple battery cells into a capacitor and then transferring the
buffered energy into one or more battery cells of the multiple
battery cells.
7. The system of claim 1, wherein the multiple battery cells of
each battery module are connected in series.
8. The system of claim 1, wherein the pack control unit is
configured to balance the battery cells of a battery pack by
discharging a battery cell into a resistor.
9. The system of claim 1, wherein the module control units and the
pack control unit of a battery pack are connected together in
series using the SPI bus.
10. The system of claim 1, wherein the module housing of each
battery module includes electrical connectors to separably
electrically connect the battery module to other battery modules of
a battery pack.
11. The system of claim 1, wherein the module housing of each
battery module includes a heat sink.
12. The system of claim 11, wherein the heat sink is an aluminum
heat sink.
13. The system of claim 1, wherein the enclosure of each battery
pack is an IP67 compliant housing, and wherein each enclosure
includes one or more IP67 rated electrical connectors that provide
the only electrical connections to contents of the enclosure.
14. A battery management system for an electric vehicle,
comprising: a battery assembly including: a plurality of battery
strings connected in parallel; a plurality of battery packs in each
battery string of the plurality of battery strings, wherein each
battery pack of the plurality of battery packs includes an
enclosure which is IP67 compliant, and wherein each enclosure
includes one or more IP67 rated electrical connectors that provide
the only electrical connections to contents of the enclosure; a
plurality of battery modules packaged within the enclosure of each
battery pack, wherein each battery module of the plurality of
battery modules includes a housing to provide isolation and cooling
to contents of the housing, and wherein the housing includes one or
more electrical connectors to provide separable electrical
connection to contents of the housing; and a plurality of battery
cells packaged within the housing of each battery module; a
plurality of module control units, wherein each module control unit
(a) is a printed circuit board attached to a single battery module
of the plurality of battery modules and (b) is configured to detect
at least a voltage, a current, a humidity, and a temperature of the
plurality of battery cells of the battery module, and wherein the
module control unit attached to each battery module is separate
from the module control unit attached to another battery module; a
plurality of Serial Peripheral Interface (SPI) isolation boards,
wherein each SPI isolation board is attached to a single module
control unit of the plurality of module control units; and a
plurality of pack control units, wherein each pack control unit is
associated with a single battery pack of the plurality of battery
packs and is configured to perform cell balancing of the battery
cells of the battery pack based on the voltages and temperatures
detected by the module control units of the battery pack, wherein
the module control units and the pack control unit of each battery
pack are connected together using a Serial Peripheral Interface
(SPI) bus, and wherein the SPI isolation board attached to each
module control unit isolates SPI signals from the module control
unit to the pack control unit.
15. The system of claim 14, wherein the electric vehicle is an
electric bus, and wherein the plurality of battery packs are
positioned under a floor of the bus.
16. The system of claim 14, further including an energy storage
master control unit electrically connected to the plurality of
packs control units, the energy storage master control unit being
configured to monitor a state of health of the battery cells of the
battery assembly and disconnect a battery string of the plurality
of battery strings from service based on the state of health of a
battery cell in the battery string to allow the vehicle to continue
operating using the remaining battery strings.
17. The system of claim 14, wherein the pack control unit of each
battery pack is configured to balance the battery cells of the
battery pack by buffering energy from some battery cells into a
capacitor and then transferring the buffered energy into other
battery cells.
18. The system of claim 14, wherein the housing of each battery
module includes a heat sink.
19. The system of claim 18, wherein the heat sink is an aluminum
heat sink.
Description
BACKGROUND
A BMS, or Battery Management System is a device or multiple devices
that control some or all aspects of an advanced energy storage
system. Some aspects that may be controlled include monitoring
voltages of each cell or groups of energy storage cells, monitoring
current, monitoring temperatures throughout energy storage
units(s), calculating States of Charge (SoC), calculating and/or
tracking States of Health (SoH), and/or modifying State of Charge
to balance the storage unit voltages or SoC's.
A BMS may be used in any number of applications ranging anywhere
from vehicles to cell phones to laptops to large stationary grid
balancing plants. A BMS will typically be used on an advanced
battery system consisting of many cells connected in a
series/parallel configuration, although occasionally a BMS may be
used on a less advanced battery system that needs a longer lifespan
from the batteries such as in a vehicle application or an
ultracapacitor system requiring precise control over its cell
voltages and SoC's.
The Battery Management System in any system may report information
about the system back to a central computer or control aspects of
the battery system itself. Much of the function of a BMS will be
determined at the design stage of a particular implementation,
however it will always be used to collect data about the battery
system and calculate important parameters, then either transmit or
use that data to adjust aspects of the energy storage system.
What is needed is an improved battery management system to better
balance and manage cells.
SUMMARY
The invention provides improved battery management systems and
methods. Various aspects of the invention described herein may be
applied to any of the particular applications set forth below. The
invention may be applied as a standalone battery management system
or as a component of an integrated solution for battery management.
The invention can be optionally integrated into existing business
and battery management processes seamlessly. It shall be understood
that different aspects of the invention can be appreciated
individually, collectively or in combination with each other.
In one embodiment, a battery management system includes: a
plurality of local module units, wherein each local module unit
monitors at least a cell voltage, temperature, humidity and current
from a plurality of battery cells; at least one pack master board
for aggregating data from and communicating with the plurality of
local module units; an energy storage master for interfacing with a
vehicle master controller; and an external charger, the external
charger in communication with the vehicle master controller. The
pack master board communicates with the energy storage master to
command charge transfer between the plurality of battery cells.
Other goals and advantages of the invention will be further
appreciated and understood when considered in conjunction with the
following description and accompanying drawings. While the
following description may contain specific details describing
particular embodiments of the invention, this should not be
construed as limitations to the scope of the invention but rather
as an exemplification of preferable embodiments. For each aspect of
the invention, many variations are possible as suggested herein
that are known to those of ordinary skill in the art. A variety of
changes and modifications can be made within the scope of the
invention without departing from the spirit thereof.
INCORPORATION BY REFERENCE
All publications, patents, and patent applications mentioned in
this specification are herein incorporated by reference to the same
extent as if each individual publication, patent, or patent
application was specifically and individually indicated to be
incorporated by reference.
BRIEF DESCRIPTION OF THE DRAWINGS
The novel features of the invention are set forth with
particularity in the appended claims. A better understanding of the
features and advantages of the present invention will be obtained
by reference to the following detailed description that sets forth
illustrative embodiments, in which the principles of the invention
are utilized, and the accompanying drawings of which:
FIG. 1 illustrates an example of an architecture of a battery
management system, in accordance with embodiments of the
invention.
FIG. 2 illustrates an example of an overall system architecture of
various levels of controllers, in accordance with embodiments of
the invention.
FIG. 3 illustrates examples of arrangements and interconnections
within packs and strings, in accordance with embodiments of the
invention.
FIG. 4 illustrates one example of circuitry used to implement a
Local Module Unit, in accordance with embodiments of the
invention.
FIG. 5 illustrates an example of the layout of a Local Module Unit,
in accordance with embodiments of the invention.
FIG. 6 illustrates an example of the architecture through which the
Vehicle Master Controller interfaces with the Energy Storage Master
to control operation of battery packs, in accordance with
embodiments of the invention.
FIG. 7A illustrates an example of a block diagram of an Energy
Storage Master's connections, in accordance with embodiments of the
invention.
FIG. 7B illustrates a flowchart of an example of behavior of an
Energy Storage Master, in accordance with embodiments of the
invention.
FIG. 8 illustrates a block diagram for an example of a Pack Master
Unit, in accordance with embodiments of the invention.
FIG. 9 illustrates an example of an architecture for a Pack Master
Unit, in accordance with embodiments of the invention.
FIG. 10 illustrates an example of a flowchart illustrating behavior
of a Pack Master Unit, in accordance with embodiments of the
invention.
FIG. 11 illustrates an example of a block diagram of a Local Module
Unit, in accordance with embodiments of the invention.
FIG. 12 illustrates an example of an architecture for a Local
Module Unit, in accordance with embodiments of the invention.
FIG. 13 illustrates an example of the timing of the SPI Interface,
in accordance with embodiments of the invention.
DETAILED DESCRIPTION
In the following detailed description, numerous specific details
are set forth in order to provide a thorough understanding of the
invention. However it will be understood by those of ordinary skill
in the art that the invention may be practiced without these
specific details. In other instances, well-known methods,
procedures, components and circuits have not been described in
detail so as not to obscure the invention. Various modifications to
the described embodiments will be apparent to those with skill in
the art, and the general principles defined herein may be applied
to other embodiments. The invention is not intended to be limited
to the particular embodiments shown and described.
Lithium Ion battery systems require cell balancing throughout their
lifetime in order to maintain a maximum amount of usable energy and
cycle life of the batteries. A battery management system (BMS) in
accordance with embodiments of the present invention may balance
these cells and create a communication and control link to the rest
of the system in which the batteries are installed. The
effectiveness of the system is highly affected by the way in which
this system is organized and implemented. Since all battery types
can benefit from cell balancing and this system can react to other
chemistries by changing the firmware in a mater pack, systems and
methods for implementing a BMS as further described herein can
adapt to other types of cell chemistries with proper programs
controlling balance and charge.
In an aspect of embodiments of the present invention, a battery
management system (BMS) is provided. As further described below,
the physical layout of the BMS may include many Local Module Units
(LMU's), with low amounts of processing power to provide local
information at a module level. Each Local Module Unit may be
attached via a relatively long isolated communication link to an
intermediate controller which consolidates information and makes
decisions about cell balancing. The intermediate controller may
relays macro-level information to an Energy Storage Master (ESM)
controller, and the Energy Storage Master may make high level
decisions about the Energy Storage System and potentially control
charge algorithms and communication. This master level controller
may also provide feedback to other controllers on a Controller Area
Network (CAN), e.g., ISO 11898 which may define the physical later,
although the specific communication language is not important. As a
result, a very high rate cell balancing creates the opportunity to
balance cells while charging the energy storage system at very high
rates. Such rates may exceed five times the C rate of the storage
system. Further, the very high rate cell balancing is the key to
charging batteries at extreme rates of charge. Balancing can be
accomplished suing resistive shunt bleed or active balancing with
isolated DC-DC converters or capacitive switching, or any other
method known to practitioners of the art.
System Architecture:
Referring to FIG. 1, in one embodiment, a battery management system
includes several subsystem blocks, an Energy Storage Master unit
100, and Traction Pack Systems 104. The Energy Storage Master may
interface with the Vehicle Master Controller (ZR32-A) 101 with a
pass through from the Energy Storage Master 100 by way of CAN or
other communication method to an External Charger 102. The Vehicle
Master Controller 101 may interface with the External Charger 102
either directly or through a charging station interface. The energy
storage system may include several strings of batteries 103 in an
electric vehicle. Within each of these strings 103, there may be
packs 104, and each pack is comprised of several battery modules.
The Traction Packs 104 may communicate to the Energy Storage Master
100 by way of a second CAN bus. Two packs 104 may make up a string
103. The packs may be controlled by a pack master, which may
communicate with the Energy Storage Master 100 using a single CAN
bus for the entire system. Each pack master may communicate with
its Local Module Unit using an Serial Peripheral Interface (SPI)
bus. The Local Module Unit and Pack Master communications may be
isolated. In one embodiment, the battery modules containing 10
prismatic battery cells each, there are 8 battery modules per pack,
2 packs per string, and a variable number of strings per vehicle
(typically 3 to 4).
Referring to FIG. 2, an example of an overall system architecture
of various levels of controllers is illustrated. In one embodiment,
the system architecture includes three modules, one to monitor
groups of battery cells 201, a second processor module to collect
further information about the cell groups 202, and a third module
203 that takes high-level information from each cell group
processor to process and pass on to other vehicle controllers or
charger controllers. In this implementation the cell group monitor
201 can observe anywhere from 4 to 12 cells and monitor up to 8
temperatures in addition to the die temperature of the monitor. In
addition, the monitor 201 can control discharge or charge transfer
between cells in the group. The second processor module 202
monitors all cell group voltages and temperatures and uses that
information to command the discharge or charge transfer between
cells in each cell group 201. Up to 16 cell groups can be connected
together and controlled with a single processor module 202. In this
implementation the third controller module 203 communicates with
the processor module through an electrically isolated CAN
communication module, however this communication method is not
required. Any conductive, opto-isolated, or magnetically coupled
physical communication method can be used to communicate via CAN,
RS-485, or some other multi-master communication standard known to
masters of the art. This communication master controller 203 can be
linked with as many cell group controllers 202 as is available via
the standard; in this implementation the controller 203 is
connected to 6 or 8 cell group controllers 201. Each battery module
may include a Local Module Unit which is a board further described
below.
Cell balancing at the cell group module level can be implemented in
a number of ways. In one implementation the cell group module 201
may be commanded by the cell group controller 202 to discharge
cells at up to 20 W of power per cell, for example. Heat is
dissipated through the circuit board and can also be transferred
into a heatsink for a faster discharge rate. Removing energy at a
high rate enables the battery cells within the module 201 to
balance very quickly. Instead of discharging cells into resistors
and creating heat, charge balancing can be done via a charge
shuttling routine. Energy can be buffered into a capacitor or
supercapacitor from one or many cells, then transferred into a
single cell by using the cell group module 201 to turn on
transistors moving charge into the cell. By using transistor level
components rated for the maximum voltage of the module, the system
can provide isolation for all cells attached through transistors to
the energy storage device. If done in rapid succession, the module
201 can move energy from the overall module 201 into a specific
cell resulting in a highly efficient method of balancing. Resistors
can still be utilized to drop module voltages with respect to other
modules. Using this method allows the cells controlled by the cell
group controller 202 to balance fully, and by using intelligent
controls, can balance every cell connected to the large network
connected to the Energy Storage Master Controller 203. A third
balancing possibility would be to use an isolated DCDC converter
attached at the module level that could charge an individual cell
based on transistor switching at any one cell on the module.
Other BMS systems, have a number of faults which are addressed by
embodiments of the present invention. For example, other BMS
systems may require a significant number of wires (e.g., 144 per
pack) which can result in extra assembly work, large wiring
harnesses, more failure points, and added weight. In addition,
other BMS systems often have insufficient voltage resolution which
may not be sufficient to balance individual cells with nominal
voltages of 2.3V. Lastly, other BMS systems may be inadequate for
fast charging of energy storage systems at 6 C rates. In
particular, active balancing of cells during charge events may not
be able to be achieved.
By utilizing a multi-cell battery stack monitoring microprocessor
chip, for example LT-6802-1 from Linear Technology, the complexity
of writing required may be greatly reduced. Thus, less wiring may
be required to gather data from groups of cells and send
consolidated information from each cell and module which can be
aggregated back to the energy storage master for decision making. A
multi-cell battery stack monitoring microprocessor chip may be used
as the central processor on the Local Module Unit. This may enable
a simplification of the BMS which may allow removal of excess
wiring (e.g., the removal of 140 wires per pack). Voltage
resolution may also be improved, for example, with overall string
voltage and current with selectable cell voltages at a high
resolution of +/-0.05V.
Use of a multi-cell battery stack monitoring microprocessor chip,
for example LT-6802-1 from Linear Technology, may have several
benefits including: enabling fast charging at 6 C rates, active
balancing during fast charging at 6 C rates, using 20 W bleed
resistors per cell versus 1 W typical. Other benefits may include:
humidity or water detection in battery packs (may aid in detection
of compromised integrity of back pack enclosures and may provide
advanced warning of potential field issues), efficient cell
balancing (shuttling energy between cells versus resistive
dissipation of heat), and bypass capability per cell to allow limp
home mode (providing emergency power to limp home under derated
conditions, and where an intermittently functioning cell would
typically trigger the pack to be taken offline line, an
intermittent cell could be bypassed allowing some power from the
pack to be used for vehicle propulsion).
Thus, a multi-master implementation may control battery groups
independently and send information about the pack to the Energy
Storage Master and the rest of the battery groups. The information
that is distributed between the controllers can be used for
purposes such as energy tracking, verification of sensor feedback,
and distribution of battery group information to allow balancing
and management between groups. The Energy Storage Master controller
can utilize battery group information such as State of Charge,
Current, Voltage, Temperature, and other relevant information to
interface with chargers or vehicle controllers. For example, if a
short is ever detected through the BMS, the system may disconnect
each sub-pack in the string where the fault is detected and that
will isolate the fault. Thus, the BMS further ensures a level of
safety which is necessary in the event of a major crash or failure
of the isolation system.
Thus, an integrated BMS may enable cell monitoring, temperature
monitoring, cell balancing, string current monitoring, and charger
control integration. The BMS may be integrated into battery packs
to give early warning to potential problems with weaker battery
cells within the string of a battery back. The BMS may give
feedback on cell voltages and temperatures within the battery
modules in order to ensure a healthy battery pack.
Referring to FIG. 3, examples of arrangements and interconnections
within packs and strings are shown. The power connections in a
string 30 may consist of two packs 20 in series and those series
packs may be paralleled with two other packs. Each pack may consist
of eight Local Module Units 10 connected in series. Each Local
Module Unit may balance ten battery cells also connected in series.
Each cell may have a nominal voltage of 2.3V or some other nominal
voltage relating to lithium chemistry batteries. The cell voltage
can range from 2.0V to 2.8V depending upon its state of charge and
whether it is being charged or discharged. Nominal system voltages
are therefore 23V per Local Module Unit 10, 184V per pack and 368V
per string. Maximum voltages are 28V per Local Module Unit 10, 224V
per pack and 448V per string 30. All power should be (but does not
necessarily need to be) isolated from the vehicle chassis. The
Local Module Units 10 may be connected together to communicate with
each other using standard communication protocols. For example, the
SPI communication protocol 12 may allow all of the Local Module
Units to communicate at the same time. Further, each Local Module
Unit may have an address to identify whether that Local Module Unit
should communicate with the Pack Master.
In one embodiment, the electronic assemblies may be designed such
that there is sufficient design margin to account for component
tolerances and the manufacturer's specifications are not be
exceeded. With respect to electrical maximums, in one embodiment,
the pack level maximum voltage is 224 VDC, the string level maximum
voltage 448 VDC, and the pack level maximum operating current range
is -1200 ADC to 1200 ADC.
In one embodiment, signal and low power wiring will be selected to
meet the following table:
TABLE-US-00001 AWG ohms/kft Max current A 12 20 14 15 16 18 20
10.15 11 22 16.14 7 24 25.67 3.5 26 40.81 2.2 28 64.9 1.4 30 103.2
0.86
Each connection may have its maximum expected current specified so
that the appropriate wire gauge and connector pin ratings can be
easily determined. Further, in one embodiment, any wiring that is
not off the shelf may be 18 AWG or larger.
In one embodiment, high power wires are selected to meet the
following table:
TABLE-US-00002 length in feet for total circuit for secondary
voltages only - do not use this table for 600 Volt in-line
applications AMPS 100' 150' 200' 250' 300' 350' 400' 100 4 4 2 2 1
1/0 1/0 150 4 2 1 1/0 2/0 3/0 3/0 200 2 1 1/0 2/0 3/0 4/0 4/0 250 1
1/0 2/0 3/0 4/0 300 1/0 2/0 3/0 4/0 350 1/0 3/0 4/0 400 2/0 3/0 450
2/0 4/0 500 3/0 4/0 550 3/0 4/0 600 4/0 REQUIRED CABLE SIZES SHOWN
IN AWG NUMBERS The total circuit length includes both welding and
ground leeds (Based on 4-Volt drop) 60% duty cycle.
In one embodiment, the bus bar may be 1/8'' by 1'' cross section or
larger.
With respect to timing, in one embodiment, a fault is detected in
500 mS or less. The 500 mS determination is based on a
communications failure happening, and waiting 5.times. the
communications data rate before triggering a fault. In this
embodiment, this is expected to be the longest time for a failure
to be detected so as to prevent damage to batteries by heat,
voltage (under/over), and current.
In one embodiment, the contactor must be opened within 500 mS after
a fault is detected and response to commands must occur in 300 mS
(100 ms Pack Master (PM) to EMC), 100 mS Energy Storage Master
(ESM) to Vehicle Master Controller (VMC), and 60-75 mS VMC to
contactor).
In one embodiment, the CAN communicates at 125 kbps, which impacts
the maximum bus length per the table below.
TABLE-US-00003 Bit Rate Bus Length Nominal Bit-Time 1 Mbit/s 30 m 1
.mu.s 800 kbit/s 50 m 1.25 .mu.s 500 kbit/s 100 m 2 .mu.s 250
kbit/s 250 m 4 .mu.s 125 kbit/s 500 m 8 .mu.s 62.5 kbit/s 1000 m 20
.mu.s 20 kbit/s 2500 m 50 .mu.s 10 kbit/s 5000 m 100 .mu.s
The cable length of stub may be limited to 1 meter. The system may
monitor all cell voltages, currents and temperatures, and bleed off
excess voltages in the form of radiated heat. Noise from several
possible on-board sources such as Traction Motor/Controller 12.5
kHz, VFD's .about.4 kHz, etc. may be handled such that they do not
cause non-operation. In some embodiments, this may be accomplished
by way of Galvanic Isolation at levels up to 2500 VDC. Voltage
spikes from the charging system with primary fundamental at 7 kHz
with first harmonic at 14 kHz also do not disable the system. In
some embodiments, this may be accomplished by way of Galvanic
Isolation at levels up to 2500 VDC at the Local Module Unit and CAN
transceiver.
In one embodiment, the system may incorporate electronics which
meet AEC-Q200-REV C and AEC-Q101-REV-C Automotive Grade
requirements from -40 C to +125 C. To meet safety standards, all
high voltage arrays may be clearly labeled and the system may not
have any exposed voltages over 35V. It may be desired that a
differential temperature between any packs be less than 20 C. This
could be an indication of some sort of cell imbalance or failure.
Upper string and lower string are expected to have differences
exceeding this amount, so only packs within the same string may be
compared. The maximum charging current may be up to 1,100 A for the
entire bus and not to exceed 325 A per pack. The opening of
overhead emergency hatches may disable charging.
FIG. 4 illustrates one example of circuitry used to implement a
Local Module Unit 10. In FIG. 5, an example of the layout of a
Local Module Unit 10 is shown. FIG. 5 illustrates one layer of a
prototype Local Module Unit board 10. This board may be used to
monitor cell voltages and temperatures at the module level and
report information about the module to a microcontroller. In some
instances, the microcontroller may be located on the Local Module
Unit itself and may report higher level information to another
microcontroller.
Vehicle Master Controller:
Referring to FIG. 6, an example of the architecture through which
the Vehicle Master Controller interfaces with the Energy Storage
Master to control operation of battery packs is illustrated. The
Vehicle Master Controller may interface with the Energy Storage
Master which may receive aggregated data from each of the battery
packs through Pack Master Boards on each battery pack. Each pack
may have its own BMS and therefore may operate as a complete unit
independently from other packs, but may also integrate with a
master controller to provide greater overall functionality, such as
functionality that may be achieved through aggregation and
consolidation of information to the Vehicle Master Controller.
In one embodiment, as shown in FIG. 6, each battery module 600 may
have a Local Module Unit 601 which feeds data to a Pack Master 610.
The Pack Master 610 may then send aggregated data back to an Energy
Storage Master which may interface with a Vehicle Master
Controller. The energy storage master unit may communicate with all
Pack Master units 610, a bus controller, and a curbside charger(s),
and may keeps track of voltage, current 604, temperature, humidity,
state of charge (SOC) and state of health (SOH) for all cells
within each of the battery modules 600. Thus, each pack may be
addressable and may be queried as to the health and status at any
time. If there is ever a problem with an individual battery cell,
an entire string may be automatically removed from service to allow
the vehicle to continue operating in a reduced capacity mode until
a vehicle returns from operation. The Energy Storage Master
controller may provide information to the Vehicle Master Controller
when necessary and may create a user-friendly energy storage
interface to the vehicle. Thus, it may be possible to have greater
visibility into the operation of the vehicle.
To accomplish the communication, each battery pack may have a BMS
harnessing, BMS boards that maintain the cells attached to each
battery module 600, a contactor 611 and a fuse 612. All of the
modules 600 may be connected in series with a bus-bar 613 and may
be secured in place and contact a heat-sink along the back side
which may flow coolant through the vehicle electrical cooling
system. The cooling system may remove the heat radiated from the
road surface and may additionally help to reject a small amount of
heat generated by the battery cells and electrical connections. The
BMS, contactor 611 and fuse 612 may have a compartment at the end
for the pack that is accessible from underneath or the top of the
pack in the event that a repair is necessary.
In one embodiment, the Vehicle Master Controller (VMC) may be
responsible for receiving the battery data from the Energy Storage
Master, displaying state of charge and other battery information to
a vehicle operator, and controlling the status of the contactors
based on data received from the Energy Storage Master. When a
contactor 611 is open, it may mean that it is disabled and not
making a connection, and when a contactor 611 is closed, it may
mean that it is enabled and connected. If the contactor 611 is off,
it may be based on local warning or error signals using the CAN
request to Vehicle Master Controller via the Energy Storage Master.
The Vehicle Master Controller may have additional functions not
related to the BMS system.
The Vehicle Master Controller may have various contactors installed
in the vehicle--(1) HV contactors (precharge, HV+, HV-), (2)
battery contactors (string 1, string 2, string 3, string 4), (3)
overhead charge contactors (AutoChg+, AutoChg-), and manual charge
contactors (ManChg1+, ManChg1-, ManChg2+, ManChg2-).
Error conditions may result in a CAN message request for the pack
contactor 611 to open or disconnect. Some conditions may result in
a request for the contactor 611 to open immediately. For example,
if voltage in excess of 440 Volts for a bus (equivalent to 220
Volts per pack) is detected, the following contactors may be opened
as quickly as possible in the following order, and the operator may
be notified of a serious fault: (1) open charge contactors, (2)
open HV contactors, and (3) open battery contactors. As another
example, if the current is in excess of 350 Amps, either charging
or discharging, and this condition has existed continuously for
five seconds, a request may be made to open the contactor for the
string exceeding this limit. In another example, if the temperature
is in excess of 65 degrees Celsius, a request may be made to open a
string contactor and notify the operator of a fault.
Various warning conditions may be reported in a CAN message. These
conditions may result in a contactor being opened, but a
determination may be made by the EMC or Vehicle Master Controller
based on the information provided by the Pack Master 610. Along
with the warning messages, the system may work to respond to a
problem or correct a problem, for example, by cell balancing.
Warning messages and system responses may include the
following:
(1) Voltage in excess of 430V for the vehicle (equivalent to 215V
per pack): Vehicle shall terminate charging and open the charge
contactors between 500 mS and 1.5 S after detection of over-voltage
condition;
(2) Under-voltage: Normal operation shall continue. No warnings
will be provided. State of charge should be an indicator of this
warning;
(3) Voltage imbalance: If any two strings are within 10V of each
other, they can be connected. If there is a greater than 10V or 10%
SoC difference between two strings, connect only the string
contactor for the higher voltage of SoC. Report lower performance
to driver while the strings are disconnected. When the higher
voltage or SoC string depletes to the point where it is within 10V
of another string, the other string can be connected;
(4) Current imbalance: For a measured Current Imbalance (at the
Energy Storage Master Level) of greater than 100 A between strings,
the string that is different shall: (a) If overall string current
is .+-.20 A, request string disable. (b) If overall string current
is greater than .+-.20 A; do not disable and indicate a Warning
Flag to the operator;
(5) Temperature in excess of +58 C: The operator shall be notified
of a temperature warning, and the charge and discharge shall be
derated according to the following limits: 70% of nominal for
temperatures from -30 C to 70 C and SOC from 0 to 100%, 50% of
nominal for temperatures from -30 C to 70 C and SOC from 0 to 100%,
and 0% of nominal for temperatures from -30 C to 70 C and SOC from
0 to 100%. In practice, any derating may be achieved with the
system simply by programming the cutoff limits in a lookup table.
This may be useful for derating the pack based on temperature of
the cells to prevent damage;
(6) Temperature below -25 C: Normal operation will be allowed. It
is expected that during operation, the cell temperatures will
increase;
(7) Lose Pack Contactor/Battery Cell/Battery Error: The problem
string contactor will be commanded to open. The contactor will
remain open until the condition no longer exists;
(8) Lose more than 1 string: All of the problem string contactors
will be commanded to open. The contactor will remain open until the
condition no longer exists. The driver shall be informed of the
warning;
(9) Loss of communications with Energy Storage Master: Keep
contactors connected. Indicate yellow alarm at dash;
(10) Loss of communications with Pack Master(s): Keep contactors
connected. Indicate yellow alarm at dash;
(11) Master Switch turned off while charging: The following events
must occur in sequence: (a) Disable Charging, (b) Disable Charger
Contactors, (c) Disable HV Contactors, and (d) Disable Battery
Contactors;
(12) Emergency Hatch Open: The following events must occur in
sequence: (a) Disable Charging, (b) Disable Charger Contactors, (c)
Display screen text, "Hatch Open! Close hatch & re-dock to
continue charging," and (d) Latched off until vehicle movement;
(13) Vehicle Movement while charging: The following events must
occur in sequence: (a) Disable Charging, and (b) Disable Charger
Contactors;
(14) Fused Contactors: A secondary detection method may be used for
warning.
During normal operation, when no faults have been detected, the
contactors may be configured as follows during each of the
operation states of the vehicle:
(1) Vehicle Powered Off: All Contactors Open;
(2) Vehicle Overhead Charging: HV Contactors Closed, Battery
Contactors Closed, Overhead Charge Contactors Closed;
(3) Vehicle Manual Charging, Port 1: ManChg 1.+-.Closed, HV
Contactors Closed, Battery Contactors Closed;
(4) Vehicle Manual Charging, Port 2: ManChg 2.+-.Closed, HV
Contactors Closed, Battery Contactors Closed, Overhead Charge
Contactors Open; and
(5) Vehicle Running: HV Contactors Closed, Battery Contactors
Closed, Manual Charge Contactors Open, Overhead Charge Contactors
Open.
Energy Storage Master (ESM) Unit:
Referring to FIG. 7A, an Energy Storage Master's connections block
diagram is shown. The Energy Storage Master 700 may have several
capabilities. Its main function is to interpret Vehicle Master
Controller commands to and from the Pack Masters (via connections
701 and 702). It also collects a database for display to the
Vehicle Master Controller for High/Low/Average Voltage, SOC, SOH,
and High/Low/Average temperatures for the Traction Packs. It keeps
track of which cell has Temperature or Voltage extremes. It also
has the ability to interface with the Fast Charge System relating
required Voltages and Currents indicated by SOC.
Referring to FIG. 7B, the Energy Storage Master: (1) receives and
decodes messages from the Pack Master (711), (2) encodes and
transmits messages to the Pack Master (718), (3) receives and
decodes messages from the Vehicle Master Controller (711), (4)
encodes and transmits messages to the Vehicle Master Controller,
(5) consolidates all messages from Pack Masters and send data to
the Vehicle Master Controller (719), (6) updates string data and
determines how many strings are present (712), (7) determines if
charge mode is requested (714), and (8) runs a charge algorithm for
the correct one of four available charge states (715).
The Energy Storage Master may run on an internal loop for sending
CAN bus messages. For example, the Energy Storage Master internal
main loop may run on a 100 ms, 250 ms, and 1000 ms period for
sending CAN bus messages, and the messages therefore may be sent at
the following times each second: 100 ms, 200 ms, 250 ms, 300 ms,
400 ms, 500 ms, 600 ms, 750 ms, 800 ms, 900 ms and 1000 ms. FIG. 7B
illustrates a behavioral block diagram for the actions of the
Energy Storage Master.
In one embodiment, connectors and pinouts for the Energy Storage
Master may be as follows:
Interface Name: ESM CAN
The cable harness that connects to this interface is XCAN.
Connector PN: Deutsch DT 06-3S
TABLE-US-00004 TABLE 1 ESM CAN Bus Pin Out Pin Signal Description
Current Voltage Isolation A CAN Hi Blk 10 mA 5 V 500 Vcont B CAN
Low Red 10 mA 5 V 500 Vcont C Shield Shield 10 mA +/-0.3 V
Interface Name: ESM Power The cable harness that connects to this
interface is TBD. Connector PN: Omron S82S-7705
TABLE-US-00005 TABLE 2 5 V ESM Power Pin Out Pin # Signal
Description Current Voltage Twisted VIN 5VDC 5 V (Pink) 400 mA 24 V
GND GND Ground (White) 400 mA 24 V
Pack Master Unit:
FIG. 8 illustrates a block diagram for an example of a Pack Master
Unit 800. In one embodiment, the Pack Master Unit 800 has several
capabilities and its primary function is to provide power as half
of a string of battery cells. In one embodiment, the position of
the Pack Master Unit 800 as the upper or lower unit in a string is
interchangeable. The Pack Master Unit 800 may also monitor all
Cells located inside Battery Module units and alert the Energy
Storage Master if certain operation limits are exceeded. The Pack
Master Unit 800 may communicate with the Energy Storage Master via
CAN message protocols. The Pack Master Unit 800 may communicate to
Local Module Units via SPI from the Pack Master to the Local Module
Unit. The micro controller may utilize a JTAG programming interface
or any other programming interface known to experts in the art.
Optimally, a bootloader program may be loaded to the Pack Master
Unit which allows programming via the communication CAN bus.
Referring to FIG. 9, a pack master unit 910 may convert pack power
(50-240 VDC) to 24-28 VDC for a contactor and 3-5 VDC for pack
master 910, communicates to Local Module Units 901 inside of the
pack, controls contactor 911 inside pack for pack power externally
enabled/disabled, monitors individual cell voltages and command
shunt to bleed resistor if required, monitors temperature inside
individual battery modules, monitors humidity inside the pack,
monitors pack current 912 (+-30 A, +-300 A), and galvanically be
isolated from anything external to the pack.
In FIG. 10, an example of a flowchart illustrating behavior of a
Pack Master Unit is illustrated. In step 1001, the SPI Bus is read.
If 1 second has elapsed in step 1002, then the temperature is
measured from one module in step 1003. In step 1004, the Pack
Master Unit may check for a Pack enable message. Every 250 mS, in
step 1005, the CAN bus is read from the LMU and the module Voltage
is read and converted to float. In step 1006, the measure of the
Current Transducer is taken over a median of 100 samples. If the
current is less than 30 A in step 1007, in step 1008 the Pack
Master Unit may use a high current channel. Otherwise, the Pack
Master Unit may use the low current channel in step 1009. In Step
1010, the Pack Master Unit may determine State of Charge using open
circuit voltage if the current is less than a certain threshold.
Otherwise, the Pack Master Unit may determine State of Charge using
a Coulomb count. In step 1011, the Pack Master Unit may enable the
contactor using CAN request to Vehicle Master Controller via the
Energy Storage Master.
In one embodiment, voltage ranges for the Pack Master Unit range
from 5 VDC+-30 mV, from Isolated Power Supply Unit (V-Infinity
PTK15-Q24-S5-T or equivalent. For the SPI: 5.0 VDC TTL level, CAT
5e non-shielded connector. With respect to isolation, in one
embodiment 500V continuous isolation and in one embodiment, 2500V
peak isolation (i.e. continuous and intermittent short bursts).
There may be two primary software loops, one running every 250 mS
and the other running every 100 mS, for example.
In one embodiment, connectors and pinouts for the Pack Master Unit
may be as follows:
Internal Interfaces
Interface: Pack Signal
The external pack signal cable is a custom cable that connects each
pack master to the junction box.
Connector PN: Harting 0914002 2751
Mate Connector PN: Hailing 0914002 2651
TABLE-US-00006 TABLE 3 External Pack Signal Pin Out Pin # Signal
Description Current Voltage Isolation Twisted 1 24 V SW 24 V
Switched 400 mA 24 V 2 GND Ground, 24 V return 400 mA +/-0.3 V 3
Contactor+ Contactor control positive 1.5 A pk 28 V 4 Contactor-
Contactor control negative 1.5 A pk 28 V 5 CAN A CAN bus signal A
10 mA 5 V 500 Vcont 6 CAN B CAN bus signal B 10 mA 5 V 500 Vcont 7
Shield Shielding +/-0.3 V 8 Case GND Chassis ground +/-0.3 V
The external pack signal connector will connect to four different
connectors in the pack master through the internal pack Y cable.
Interface: 24V Pack Power Supply Module 24V is supplied to the pack
power supply module. Pack Y cable mate. Connector PN: DT06-4S Mate
Connector PN: DT04-4P
TABLE-US-00007 TABLE 4 24 V Pack Power Supply Module Pin Out Pin #
Signal Description Current Voltage Twisted 1 GND Ground 400 mA 28 V
2 24 V SW 24 V Switched 400 mA 28 V 3 Unused 4 Unused
Interface: 5V PackMaster Power 24V is supplied to the pack power
supply module. Pack Y cable mate. Connector PN: DT06-2S Mate
Connector PN: DT04-2P
TABLE-US-00008 TABLE 5 5 V PackMaster Power Pin # Signal
Description Current Voltage Twisted 1 GND Ground 400 mA 5 V 2 24 V
SW 24 V Switched 400 mA 5 V
Interface: Contactor Control 24 to 28V, 1.5Apk for 32 ms transition
and 0.1 A hold current for a Gigavac GX15. Pack Y cable mate.
Connector PN: Spade Mate Connector PN: Spade Recept.
TABLE-US-00009 TABLE 6 Contactor Control Pin Out Pin # Signal
Description Current Voltage Twisted Coil+ (red) Contactor control
positive 1.5 A pk 28 V Coil- (black) Contactor control negative 1.5
A pk 28 V
Interface: Pack Master CAN The cable harness that connects to this
interface is XCAN. Pack Y cable mate (Deutsch DT04-3P). Connector
PN: Deutsch DT 06-3 S Mate Connector PN: Deutsch DT04-3P
TABLE-US-00010 TABLE 7 Pack Master CAN Bus Pin Out Pin Signal
Description Current Voltage Isolation A CAN Hi Blk 10 mA 5 V 500
Vcont B CAN Low Red 10 mA 5 V 500 Vcont C unused
Interface: Case Ground This is attachment to case on the pack
master. Pack Y cable mate. Connector PN: Ring Term. Mate Connector
PN: Bolt
TABLE-US-00011 TABLE 8 Pack Master Case GND Pin Out Pin # Signal
Description Current Voltage Case GND Case ground 400 mA +/-0.3
V
Interface: Pack Master SPI The cable harness that connects to this
interface is CAT5e. Connector PN: AMP 43860-0001 Mate Connector PN:
RJ45 style
TABLE-US-00012 TABLE 9 Pack Master SPI Communication Pin Out Pin #
Signal Description Current Voltage Isolation Twisted 1 CS SPI Chip
Select 10 mA 5 V 500 Vcont Pair 3 2 MISO SPI master in slave out 10
mA 5 V 500 Vcont Pair 3 3 MOSI SPI master out slave in 10 mA 5 V
500 Vcont Pair 2 4 SCK SPI clock 10 mA 5 V 500 Vcont Pair 1 5 GND
Ground 120 mA +/-0.3 V 500 Vcont Pair 1 8 NC No Connect Pair 4 7 NC
No Connect Pair 4 6 5 V Power 120 mA 5 V 500 Vcont Pair 2
Analog Signal Connectors Two current transformers (CT) may be used
to measure the current in and out of the pack master. One may be
scaled for 0 A-30 A measurement and the other 0 A-350 A
measurements. Interface: CT Pre-Conditioning The CT
Pre-Conditioning connector connects to the hall effect sensors for
current monitoring. Connector PN: Delphi PA6-GB20 Mate Connector
PN: Delphi PA66-GF25
TABLE-US-00013 TABLE 10 CT Pre-Conditioning Pin Out Pin # Name
Description Current Voltage Twisted B 5V Sensor Power 100 mA 5 V C
GND Sensor Ground 100 mA +/-0.3 V D Hall 1 First hall -30 A to 30 A
10 mA 5 V A Hall 2 Second hall -350 A to 350 A 10 mA 5 V
High Power Connectors The high power path may be fused at 500 Amps.
0000 AWG welding cable or copper buss bars may be selected for high
current conductors. The ampacity of 4/0 welding cable may be 600 A
with a temperature rise of 20 C. The fuse rating must be below the
wiring rating in order for it to open before damage to the wiring
occurs. Interface: Pack Voltage The pack voltage harness is used to
connect the pack's battery voltage to other pack masters and to the
junction box. Connector PN: Mate Connector PN:
TABLE-US-00014 TABLE 11 Pack Voltage Pin Out Pin # Signal
Description Current Voltage 1 Battery+ Positive battery voltage 500
A 500 V 2 Battery- Negative battery voltage 500 A 500 V
Interface: LMU Terminal The LMU terminal is used to connect the
LMU's battery voltage to the pack masters. Connector PN: Terminals
Mate Connector PN:
TABLE-US-00015 TABLE 12 LMU Terminal Pin Out Pin # Signal
Description Current Voltage 1 Battery+ Positive battery voltage 500
A 220 V 2 Battery- Negative battery voltage 500 A 220 V
Interface: Fuse Terminal The Fuse terminals are connected to the
minus to fuse cable and fuse to contactor cable. Connector PN:
Terminals Mate Connector PN:
TABLE-US-00016 TABLE 13 Fuse Terminal Pin Out Pin # Signal
Description Current Voltage 1 Battery- Negative battery voltage 500
A 220 V
Interface: Contactor Terminal The Contactor terminals are connected
to the fuse to contactor cable and contactor to LMU terminal.
Connector PN: M8.times.1.25 Power Terminals Mate Connector PN:
TABLE-US-00017 TABLE 14 Fuse Terminal Pin Out Pin # Signal
Description Current Voltage 1 Battery- Negative battery voltage 500
A 220 V
Local Module Unit:
Referring to FIG. 11, an example of a block diagram of a Local
Module Unit 10 is illustrated. In one embodiment, the primary
function of the Local Module Unit 10 is to monitor the Pack Cells
located inside Battery Module units sending Voltage and temperature
conditions to the Pack Master. The Local Module Unit may also
switch on bleed resistors when told to by the Pack Master. As shown
in FIG. 11, the LTC6802-2 is a data acquisition IC capable of
measuring the voltage of 12 series connected battery cells. An
input multiplexer connects the batteries to a 12-bit delta-sigma
analog to digital converter (ADC). Communication between the
LTC6802-2 and a host processor is handled by a SPI compatible
serial interface. The LTC6802-2 also contains circuitry to balance
cell voltages. The host processor writes values to a configuration
register inside the LTC6802-2 to control the switches. The open
connection detection algorithm assures that an open circuit is not
misinterpreted as a valid cell reading. The primary cell voltage
A/D measurement commands (STCVAD and STOWAD) automatically turn off
a cell's discharge switch while its voltage is being measured. The
discharge switches for the cell above and the cell below will also
be turned off during the measurement. Two self test commands can be
used to verify the functionality of the digital portions of the
ADC. It is important to note that the LTC6802-2 makes no decisions
about turning on/off the internal MOSFETs. If signal from Pack
Master is removed for more than 2.5 seconds, the Local Module Unit
will turn off all bleed resistors in the on state and go into a
standby condition.
As shown in FIG. 12, in one embodiment, a BMS may include a Local
Module Unit 1201 which is a board that is attached to each battery
module 1200 and gathers cell voltage 1202, temperature 1203,
current 1204 and humidity 1205 from the cells in each battery
module 1200. A Local Module Unit may continuously monitor
individual cell voltages 1202, continuously monitor cell
temperature 1203, be capable of shunting individual cell voltage to
a bleed resistor, can have many temperature, voltage or other
sensors attached at the module level. In one example, a Local
Module Unit may have total power dissipation per cell at 32 W
Maximum, 20 W Bleed Resistor and 12 W Mosfet Switch, can bypass a
disabled cell with .about.7 Amps carry current, can have up to 8
temperature monitors, and can have 4 temperature monitors and 4
peripheral monitors.
The Local Module Unit may be mounted directly to the Battery Module
Unit, and an SPI Isolation Board may be mounded to the Local Module
Unit. The SPI Isolation Board may isolate SPI signals from the
Local Module Unit to the Pack Master. In one embodiment, the SPI
Isolutioni Board isolates signal levels from the Local Module Unit
to the Pack Master side at 2500V RMS for 1 minute per UL1577. In
one embodiment, the SPI Isolation Board requires an external power
source of 5 VDC+-0.5 VDC and has a current range of 2.45 mA to 90
mA. In one embodiment, the SPI Isolation Board will provide
positive indication of power applied. The SPI Isolation Board may
pass Clock signal when SPI is interrupted or removed.
In one embodiment, pinouts and connections for the Local Module
Unit and SPI Isolation Board may be as follows:
Interface: J1, J2
The cable harness that connects to this interface is CAT5e.
Connector PN: AMP 43860-0001
Mate Connector PN:
TABLE-US-00018 TABLE 15 SPI Communication Pin Out Signal Pin
Description Current Isolation CS 1 Chip Select 10 mA 500 Vcont SDO
2 Serial Data Out 10 mA 500 Vcont SDI 3 Serial Data In 10 mA 500
Vcont SCLK 4 Clock 10 mA 500 Vcont GND 5 Ground 120 mA 500 Vcont NC
6 No Connection GND 7 Ground 120 mA 500 Vcont 5VDC In 8 5VDC 120 mA
500 Vcont
Interface Name: Cell Balancing Interface Connector: Molex MX150,
0194180038 The cable harness that connects to this interface is
Battery Monitor. Connector PN: Molex MX150, 0194290015 Mate
Connector PN:
TABLE-US-00019 TABLE 16 LMU to Battery Cell Interface Signal Pin
Current Cell 1- 1 Cell 1 + Cell 2- 2 Cell 2 + Cell 3- 3 Cell 3 +
Cell 4- 4 Cell 4 + Cell 5- 5 Cell 5 + Cell 6- 6 Cell 6 + Cell 7- 7
Cell 7 + Cell 8- 8 Cell 8 + Cell 9- 9 Cell 9 + Cell 10- 10 Cell 10+
11 NC 12
Connector Name: NTC Interface The cable harness that connects to
this interface is Battery NTC. Connector PN: Molex MX150,
0194290010 Mate Connector PN:
TABLE-US-00020 TABLE 17 LMU to NTC Interface Signal Pin Current NTC
1+ 1 NTC 1- 2 NTC 2+ 3 NTC 2- 4 NTC 3+ 5 NTV 3- 6
The timing of the SPI Interface may operate in accordance with FIG.
13, as shown.
Integration within Vehicle:
In one embodiment, the design of the energy storage system
accommodates space constraints of a vehicle. For example, a battery
pack may be placed within the floor structure of a vehicle, below
the floor surface, on a low floor transit bus and be able to
maintain road clearance and approach/departure angles necessary to
comply with bus standards, for example those set by the American
Public Transit Association. Thus, a bus may also have a
conventional bus seating pattern.
A large capacity (50 Ah) cell in a series string of batteries may
be placed in parallel with additional strings and thus is
significantly safer to operate in the event of a catastrophic
failure than a parallel set of cells in series. Because lithium
cells typically fail shorted, if a failed cell is in parallel with
many other cells, then the other cells would typically discharge as
much energy as possible into the damaged cell. Typically cells are
put in parallel first to reduce the cost of battery management
systems since each cell voltage must be measured. Because of the
unique larger capacity cell, paralleling batteries before placing
them in series is no longer necessary thus increasing the safety of
the entire pack. Additionally, the anode change in the cell
chemistry provides for an intrinsically safe cell that is also at a
much higher power density. Further variations on the number of
strings of batteries allow the size of the energy storage system to
vary without having to add more controls to the vehicle or change
anything with other strings.
Integration of a cooling system may maintain the packs at
temperatures within the limits of the battery chemistry contained
within the packs. In the event of no system cooling, the energy
storage system may be operated for multiple hours in a fast charge
mode without exceeding the recommended operating temperatures.
The battery pack may also be fully IP67 compliant and reject dust
and water if submerged. The pack may be connected to the vehicle by
two IP67 rated connectors as the only electrical connections to the
vehicle which can be unlatched and pulled off quickly for ease of
maintenance. All contacts on the connector may be touch-safe and
de-energized when the connector is removed. Further, wiring and
terminations within the pack may be sized and secured for a full 12
year cycle life of the vehicle. Impedance matching between packs
may be gauged by comparing current flow through parallel strings,
therefore allowing predictive maintenance of wiring and terminal
attachments within the strings.
In one embodiment, the energy storage modules include multiple
battery cells (for example, 10 cells, each at 2.3V, 50 Ah). The
module housing may be designed to mechanically integrate and
protect the cells as well as provide cooling and controls support.
Battery management system connectors may be integrated into the
front of the module for quick connection of an externally mounted
battery management system board. Terminals may be offset and tapped
for vertical installation of attachment bolts and ease of assembly.
Modules may be isolated from each other to protect against
potential short circuiting. This may be accomplished through
material selection and post processing of aluminum heat sinks. If a
short is ever detected through the battery management system, the
system may disconnect each sub-pack in the string which will
isolate the fault to ensure safety in the event of a major crash or
failure of the isolation system.
In some embodiments, the energy system may be able to accept very
high charge and discharge rates as well as carry a large amount of
energy. Lithium titanate technology may be able to charge from 0%
SOC to 90% SOC in as little as 1 minute (60 C rate) at the cell
level and as little as 6 minutes (10 C rate) on the vehicle level.
In some embodiments, the acceptable temperature range is
-30.degree. C. to 70.degree. C. Within that range, in some
embodiments, the system may deliver over 90% of the available
energy in the pack giving an unprecedented range of temperatures in
which a vehicle can operate.
All concepts of the invention may be incorporated or integrated
with other systems and methods of battery management, including but
not limited to those described in U.S. Patent Publication No.
2008/0086247 (Gu et al.), which is hereby incorporated by reference
in its entirety.
While preferred embodiments of the present invention have been
shown and described herein, it will be obvious to those skilled in
the art that such embodiments are provided by way of example only.
Numerous variations, changes, and substitutions will now occur to
those skilled in the art without departing from the invention. It
should be understood that various alternatives to the embodiments
of the invention described herein may be employed in practicing the
invention. It is intended that the following claims define the
scope of the invention and that methods and structures within the
scope of these claims and their equivalents be covered thereby.
Aspects of the systems and methods described herein may be
implemented as functionality programmed into any of a variety of
circuitry, including programmable logic devices (PLDs), such as
field programmable gate arrays (FPGAs), programmable array logic
(PAL) devices, electrically programmable logic and memory devices
and standard cell-based devices, as well as application specific
integrated circuits (ASICs). Some other possibilities for
implementing aspects of the systems and methods include:
microcontrollers with memory, embedded microprocessors, firmware,
software, etc. Furthermore, aspects of the systems and methods may
be embodied in microprocessors having software-based circuit
emulation, discrete logic (sequential and combinatorial), custom
devices, fuzzy (neural network) logic, quantum devices, and hybrids
of any of the above device types. Of course the underlying device
technologies may be provided in a variety of component types, e.g.,
metal-oxide semiconductor field-effect transistor (MOSFET)
technologies like complementary metal-oxide semiconductor (CMOS),
bipolar technologies like emitter-coupled logic (ECL), polymer
technologies (e.g., silicon-conjugated polymer and metal-conjugated
polymer-metal structures), mixed analog and digital, etc.
It should be noted that the various functions or processes
disclosed herein may be described as data and/or instructions
embodied in various computer-readable media, in terms of their
behavioral, register transfer, logic component, transistor, layout
geometries, and/or other characteristics. Computer-readable media
in which such formatted data and/or instructions may be embodied
include, but are not limited to, non-volatile storage media in
various forms (e.g., optical, magnetic or semiconductor storage
media) and carrier waves that may be used to transfer such
formatted data and/or instructions through wireless, optical, or
wired signaling media or any combination thereof. Examples of
transfers of such formatted data and/or instructions by carrier
waves include, but are not limited to, transfers (uploads,
downloads, email, etc.) over the Internet and/or other computer
networks via one or more data transfer protocols (e.g., HTTP, FTP,
SMTP, etc.). When received within a computer system via one or more
computer-readable media, such data and/or instruction-based
expressions of components and/or processes under the systems and
methods may be processed by a processing entity (e.g., one or more
processors) within the computer system in conjunction with
execution of one or more other computer programs.
Unless specifically stated otherwise, as apparent from the
following discussions, it is appreciated that throughout the
specification, discussions utilizing terms such as "processing,"
"computing," "calculating," "determining," or the like, may refer
in whole or in part to the action and/or processes of a processor,
computer or computing system, or similar electronic computing
device, that manipulate and/or transform data represented as
physical, such as electronic, quantities within the system's
registers and/or memories into other data similarly represented as
physical quantities within the system's memories, registers or
other such information storage, transmission or display devices. It
will also be appreciated by persons skilled in the art that the
term "users" referred to herein can be individuals as well as
corporations and other legal entities. Furthermore, the processes
presented herein are not inherently related to any particular
computer, processing device, article or other apparatus. An example
of a structure for a variety of these systems will appear from the
description below. In addition, embodiments of the invention are
not described with reference to any particular processor,
programming language, machine code, etc. It will be appreciated
that a variety of programming languages, machine codes, etc. may be
used to implement the teachings of the invention as described
herein.
Unless the context clearly requires otherwise, throughout the
description and the claims, the words `comprise,` `comprising,` and
the like are to be construed in an inclusive sense as opposed to an
exclusive or exhaustive sense; that is to say, in a sense of
`including, but not limited to.` Words using the singular or plural
number also include the plural or singular number respectively.
Additionally, the words `herein,` `hereunder,` `above,` `below,`
and words of similar import refer to this application as a whole
and not to any particular portions of this application. When the
word `or` is used in reference to a list of two or more items, that
word covers all of the following interpretations of the word: any
of the items in the list, all of the items in the list and any
combination of the items in the list.
The above description of illustrated embodiments of the systems and
methods is not intended to be exhaustive or to limit the systems
and methods to the precise form disclosed. While specific
embodiments of, and examples for, the systems and methods are
described herein for illustrative purposes, various equivalent
modifications are possible within the scope of the systems and
methods, as those skilled in the relevant art will recognize. The
teachings of the systems and methods provided herein can be applied
to other processing systems and methods, not only for the systems
and methods described above.
The elements and acts of the various embodiments described above
can be combined to provide further embodiments. These and other
changes can be made to the systems and methods in light of the
above detailed description.
In general, in the following claims, the terms used should not be
construed to limit the systems and methods to the specific
embodiments disclosed in the specification and the claims, but
should be construed to include all processing systems that operate
under the claims. Accordingly, the systems and methods are not
limited by the disclosure, but instead the scope of the systems and
methods is to be determined entirely by the claims.
While certain aspects of the systems and methods are presented
below in certain claim forms, the inventor contemplates the various
aspects of the systems and methods in any number of claim forms.
Accordingly, the inventor reserves the right to add additional
claims after filing the application to pursue such additional claim
forms for other aspects of the systems and methods.
* * * * *